The largest company listed on the Dublin exchange confirmed there was also oil in two areas of the Jobi-East-1 reservoir in Uganda totalling 15 metres of net pay. The explorer's Mpyo-3 well uncovered 21 metres of oil-bearing reservoir sands.

Tullow said an accelerated drilling campaign comprising up to four Jobi-East appraisal wells was planned for the second half of 2011 to assess the full extent of this important new oil accumulation.

"The Jobi-East-1 and Mpyo-3 well results mark an excellent start to this next phase of our exploration and appraisal campaign in the Lake Albert Rift Basin," exploration director Angus McCoss said in a statement to the London stock exchange. The Dublin exchange was closed for the bank holiday.

Uganda, east Africa's third-biggest economy, is on the cusp of an oil boom with Tullow expected to start pumping crude and gas from the Lake Albert Basin in 2012.

The country had an estimated 2.5 billion barrels of oil, with about one billion barrels in proven reserves, Tullow told shareholders at a meeting in Dublin last week.

In Ghana, where the explorer drilled over a gross vertical interval of 300 metres, Tullow found 100 metres of low-porosity sandstone and three metres of 40 degree oil pay.

Drilling at all three sites has been suspended until the company is ready to conduct product testing.